Current source type inverter topological structure with energy feedback loop and control method

Abstract

The invention relates to a topological structure of a current source type inverter with an energy feedback loop and a control method. The invention relates to the technical field of power electronics and motor control, and provides a stable direct-current side current by using one switching tube and one diode so as to ensure controllable operation of a motor, and on this basis, discharge of feedback energy of the motor is realized by using only one switching tube and a resistor, so that the energy consumption is reduced. And the safety and reliability of the motor during four-quadrant operation are ensured under the conditions of topology as simple as possible and low cost. Compared with an existing current source inverter system with a DCDC preceding stage, only two switching tubes and one diode are used in function realization, the system is simplified, the reliability of the system is improved, and the cost is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of power electronics and motor control, and is a current source inverter topology structure with an energy feedback loop and a control method. Background Art

[0002] At present, inverters that realize DC to AC energy conversion can be divided into two types: voltage source inverter (VSI) and current source inverter (CSI). Each bridge arm of the VSI has an upper switch and a lower switch, and each switch has an anti-parallel diode to provide a flow path for the reverse current. CSI uses a DC voltage source to supply power on the DC side. The DC bus voltage is generally obtained by uncontrolled rectification by the previous diode converter, and then filtered and stabilized by the DC bus electrolytic capacitor to reduce system costs. On the AC side, a modulation strategy is used to generate an AC voltage with variable amplitude and frequency. VSI has a simple structure and is easy to control. In addition, due to the relatively mature technology of fully controlled power devices such as IGBT and MOSFET, VSI occupies a dominant position in vehicle-mounted motor drive systems. However, it has problems such as large switching harmonics of the output voltage, low fault tolerance under switch short-circuit faults, and operating temperature applicability. Unlike VSI, CSI has energy storage inductors on the DC side, which together with the voltage source provide a constant current for the load. Although the topology of CSI is more complex than that of VSI, it still has advantages such as being able to effectively expand the constant power operating range of high-speed PMSM, no need to consider short-circuit protection, being able to withstand higher operating temperatures, and having a long life, which can make up for some of the defects of VSI.

[0003] However, due to the efficiency and cost of the DC energy storage link and the limitations of applicable power switching devices, the application and market share of current source converter solutions in industrial scenarios are still lower than those of voltage source inverters. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention improves and simplifies the topology and introduces an energy feedback loop. While providing the current source inverter with a high-quality constant current at the front stage, it also provides a channel for energy feedback for the motor and processes the feedback energy in a timely manner, making it possible for the motor to achieve safe and reliable four-quadrant operation.

[0005] The present invention provides a current source inverter topology structure with an energy feedback loop and a control method. The present invention provides the following technical solutions:

[0006] A current source inverter topology structure with an energy feedback loop, the topology structure comprising a DC adjustable power supply U dc , switch tube S7, diode VD1, diode VD2, diode VD3, diode VD4, diode VD5, diode VD6, diode VD7, DC side inductor Ldc , switch tube S1, switch tube S2, switch tube S3, switch tube S4, switch tube S5, switch tube S6, switch tube S7, switch tube S8, resistor R, capacitor C fa , capacitor C fb , capacitor C fc and PMSM motors;

[0007] DC adjustable power supply U dc The positive terminal is connected in series with the collector of the switch tube S7; the base of the switch tube S7 is connected to the driving signal; the emitter of the switch tube S7 is connected in series with the cathode of the diode VD7; the anode of the diode VD7 is connected in series with the emitter of the switch tube S8; the base of the switch tube S8 is connected to the driving signal; the collector of the switch tube S8 is connected in series with the DC adjustable power supply U dc negative terminal.

[0008] Preferably, the anode of the diode VD7 is connected in series with a resistor R and a DC adjustable power supply U dc The negative end of

[0009] The emitter of the switch tube S7 is connected in series with the inductor L dc and the collector of the switch tube S1; the base of the switch tube S1 is connected to the driving signal; the emitter of the switch tube S1 is connected in series with the anode of the diode VD1; the cathode of the diode VD1 is connected in series with the collector of the switch tube S4; the base of the switch tube S4 is connected to the driving signal; the emitter of the switch tube S4 is connected in series with the anode of the diode VD4; the cathode of the diode VD4 is connected in series with the DC adjustable power supply U dc negative terminal.

[0010] Preferably, the emitter of the switch tube S7 is connected in series with the inductor L dc and the collector of the switch tube S3; the base of the switch tube S3 is connected to the driving signal; the emitter of the switch tube S3 is connected in series with the anode of the diode VD3; the cathode of the diode VD3 is connected in series with the collector of the switch tube S6; the base of the switch tube S6 is connected to the driving signal; the emitter of the switch tube S6 is connected in series with the anode of the diode VD6; the cathode of the diode VD6 is connected in series with the DC adjustable power supply U dc negative terminal.

[0011] Preferably, the emitter of the switch tube S7 is connected in series with the inductor L dc and the collector of the switch tube S5; the base of the switch tube S5 is connected to the driving signal; the emitter of the switch tube S5 is connected in series with the anode of the diode VD5; the cathode of the diode VD5 is connected in series with the collector of the switch tube S2; the base of the switch tube S2 is connected to the driving signal; the emitter of the switch tube S2 is connected in series with the anode of the diode VD2; the cathode of the diode VD2 is connected in series with the DC adjustable power supply U dc negative terminal.

[0012] Preferably, the cathode of diode VD1 is connected in series with the PMSM motor phase A; the cathode of diode VD3 is connected in series with the PMSM motor phase B; the cathode of diode VD5 is connected in series with the PMSM motor phase C;

[0013] The cathode series capacitor C of diode VD1 fa One end: the cathode of diode VD3 is connected in series with capacitor C fb One end: the cathode of diode VD5 is connected in series with capacitor C fc One end; capacitor C fa The other end, capacitor C fb The other end and capacitor C fc The other end is connected.

[0014] Preferably, according to the DC bus sampling current i dc and set the DC bus current i dc * and the given safe current value i during energy feedback fb *Compare to set the switch status of switch tubes S7 and S8;

[0015] According to the on-off status of the switch tube S7 and the switch tube S8, the topology structure is divided into four working modes, namely, power supply mode, inductor freewheeling mode, and energy feedback mode.

[0016] Preferably, when the topology structure is in the power supply mode, the switch tube S7 is turned on and the switch tube S8 is turned on;

[0017] When the topology structure is in the inductive freewheeling mode, the switch tube S7 is turned off and the switch tube S8 is turned on;

[0018] When the topology structure is in the energy feedback mode, the switch tube S7 is turned off and the switch tube S8 is turned off.

[0019] A method for controlling a current source inverter with an energy feedback loop, the method comprising the following steps:

[0020] Use the current sensor to sample the DC side current i in real time dc , when the sampling current i dc Less than a given i dc *, S7 opens, S8 remains open, and the power supply mode is entered, and the DC side current increases; when the sampling current i dc Greater than a given i dc *, S7 is closed, S8 remains open, and the inductor freewheeling mode is entered, and the DC side current slowly decreases; when a large amount of energy is fed back from the motor end to the DC side, S7 is closed, S8 is closed, and the energy feedback mode is entered. The current flows through the resistor to consume the feedback energy, and the DC side current is limited to the threshold i fb *.

[0021] A computer-readable storage medium stores a computer program, which is executed by a processor to implement a current source inverter control method with an energy feedback loop.

[0022] A computer device comprises a memory and a processor, wherein the memory stores a computer program, and the processor implements a current source inverter control method with an energy feedback loop when executing the computer program.

[0023] The present invention has the following beneficial effects:

[0024] Compared with the prior art, the present invention has the following advantages:

[0025] The present invention can provide a stable DC side current with a switch tube and a diode, thereby ensuring the controllable operation of the motor, and on this basis, only a switch tube and a resistor are used to realize the discharge of the motor feedback energy, thereby ensuring the safety and reliability of the motor during four-quadrant operation with the simplest topology and low cost.

[0026] Compared with the existing methods, the novel current source inverter topology structure with energy feedback loop of the present invention can ensure that the DC side provides stable DC current while handling a large amount of feedback energy transmitted from the motor end to the front stage due to working conditions such as motor braking, thereby improving the performance of the system and ensuring the safe operation of the system. Compared with the existing current source inverter system with DCDC as the front stage, only two switch tubes and one diode are used in the realization of the function, which simplifies the system, increases the reliability of the system and reduces the cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 It is a topological structure diagram of a current source inverter with an energy feedback loop;

[0029] Figure 2 The following is a logic flow chart of the mode switching judgment of the present invention;

[0030] Figure 3 A DC side current simulation waveform diagram when the current source inverter topology structure with an energy feedback loop of the present invention is adopted;

[0031] Figure 4A simulation waveform diagram of the DC side braking current when the current source inverter topology with an energy feedback loop of the present invention is adopted;

[0032] Figure 5 The three-phase current simulation waveform of the motor is shown when the current source inverter topology with an energy feedback loop of the present invention is adopted. DETAILED DESCRIPTION

[0033] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0035] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0036] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0037] The present invention is described in detail below in conjunction with specific embodiments. Specific embodiment one:

[0039] according to Figure 1-Figure 5 As shown, the specific optimization technical solution adopted by the present invention to solve the above technical problems is: the present invention relates to a current source inverter topology structure with an energy feedback loop and a control method.

[0040] The present invention provides a current source inverter topology structure with an energy feedback loop, the topology structure comprising a DC adjustable power supply U dc , switch tube S7, diode VD1, diode VD2, diode VD3, diode VD4, diode VD5, diode VD6, diode VD7, DC side inductor L dc , switch tube S1, switch tube S2, switch tube S3, switch tube S4, switch tube S5, switch tube S6, switch tube S7, switch tube S8, resistor R, capacitor C fa , capacitor C fb , capacitor C fc and PMSM motors;

[0041] DC adjustable power supply U dc The positive terminal is connected in series with the collector of the switch tube S7; the base of the switch tube S7 is connected to the driving signal; the emitter of the switch tube S7 is connected in series with the cathode of the diode VD7; the anode of the diode VD7 is connected in series with the emitter of the switch tube S8; the base of the switch tube S8 is connected to the driving signal; the collector of the switch tube S8 is connected in series with the DC adjustable power supply U dc negative terminal.

[0042] The present invention proposes a current source inverter topology with an energy feedback loop and a control method, wherein the topology structure includes a constant voltage source, a switch tube denoted as S7, a diode and a constant current source system composed of a DC side inductor, a switch tube denoted as S8 and a feedback energy discharge loop composed of a resistor, a basic current source inverter and a permanent magnet synchronous motor, etc. The current sensor is used to sample the DC side current i in real time. dc , when the sampling current i dc Less than a given i dc *, S7 opens, S8 remains open, and the power supply mode is entered, and the DC side current increases; when the sampling current i dc Greater than a given i dc *, S7 is closed, S8 remains open, and the inductor freewheeling mode is entered, and the DC side current slowly decreases; when a large amount of energy is fed back from the motor end to the DC side, S7 is closed, S8 is closed, and the energy feedback mode is entered. The current flows through the resistor to consume the feedback energy, and the DC side current is limited to the threshold i fb *.

[0043] Compared with the existing methods, the novel current source inverter topology structure with energy feedback loop of the present invention can ensure that the DC side provides stable DC current while handling a large amount of feedback energy transmitted from the motor end to the front stage due to working conditions such as motor braking, thereby improving the performance of the system and ensuring the safe operation of the system. Compared with the existing current source inverter system with DCDC as the front stage, only two switch tubes and one diode are used in the realization of the function, which simplifies the system, increases the reliability of the system and reduces the cost. Specific embodiment 2:

[0045] The difference between the second embodiment of the present invention and the first embodiment is that:

[0046] The anode of diode VD7 is connected in series with resistor R and DC adjustable power supply U dc The negative end of

[0047] The emitter of the switch tube S7 is connected in series with the inductor L dc and the collector of the switch tube S1; the base of the switch tube S1 is connected to the driving signal; the emitter of the switch tube S1 is connected in series with the anode of the diode VD1; the cathode of the diode VD1 is connected in series with the collector of the switch tube S4; the base of the switch tube S4 is connected to the driving signal; the emitter of the switch tube S4 is connected in series with the anode of the diode VD4; the cathode of the diode VD4 is connected in series with the DC adjustable power supply U dc negative terminal. Specific embodiment three:

[0049] The difference between the third embodiment of the present invention and the second embodiment is that:

[0050] The emitter of the switch tube S7 is connected in series with the inductor L dc and the collector of the switch tube S3; the base of the switch tube S3 is connected to the driving signal; the emitter of the switch tube S3 is connected in series with the anode of the diode VD3; the cathode of the diode VD3 is connected in series with the collector of the switch tube S6; the base of the switch tube S6 is connected to the driving signal; the emitter of the switch tube S6 is connected in series with the anode of the diode VD6; the cathode of the diode VD6 is connected in series with the DC adjustable power supply U dc negative terminal. Specific embodiment four:

[0052] The difference between the fourth embodiment of the present invention and the third embodiment is that:

[0053] The emitter of the switch tube S7 is connected in series with the inductor L dc and the collector of the switch tube S5; the base of the switch tube S5 is connected to the driving signal; the emitter of the switch tube S5 is connected in series with the anode of the diode VD5; the cathode of the diode VD5 is connected in series with the collector of the switch tube S2; the base of the switch tube S2 is connected to the driving signal; the emitter of the switch tube S2 is connected in series with the anode of the diode VD2; the cathode of the diode VD2 is connected in series with the DC adjustable power supply Udc negative terminal. Specific embodiment five:

[0055] The difference between the fifth embodiment of the present invention and the fourth embodiment is that:

[0056] The cathode of diode VD1 is connected in series with the PMSM motor phase A; the cathode of diode VD3 is connected in series with the PMSM motor phase B; the cathode of diode VD5 is connected in series with the PMSM motor phase C;

[0057] The cathode series capacitor C of diode VD1 fa One end: the cathode of diode VD3 is connected in series with capacitor C fb One end: the cathode of diode VD5 is connected in series with capacitor C fc One end; capacitor C fa The other end, capacitor C fb The other end and capacitor C fc The other end is connected. Specific embodiment six:

[0059] The difference between the sixth embodiment of the present invention and the fifth embodiment is that:

[0060] According to the DC bus sampling current i dc and set the DC bus current i dc * and the given safe current value i during energy feedback fb *Compare to set the switch status of switch tubes S7 and S8;

[0061] According to the on-off status of the switch tube S7 and the switch tube S8, the topology structure is divided into four working modes, namely, power supply mode, inductor freewheeling mode, and energy feedback mode. Specific embodiment seven:

[0063] The difference between the seventh embodiment of the present invention and the sixth embodiment is that:

[0064] When the topology structure is in the power supply mode, the switch tube S7 is turned on and the switch tube S8 is turned on;

[0065] When the topology structure is in the inductive freewheeling mode, the switch tube S7 is turned off and the switch tube S8 is turned on;

[0066] When the topology structure is in the energy feedback mode, the switch tube S7 is turned off and the switch tube S8 is turned off. Specific embodiment eight:

[0068] The difference between the eighth embodiment of the present invention and the seventh embodiment is that:

[0069] The present invention provides a current source inverter control method with an energy feedback loop, the method comprising the following steps:

[0070] Use the current sensor to sample the DC side current i in real time dc , when the sampling current i dc Less than a given i dc *, S7 opens, S8 remains open, and the power supply mode is entered, and the DC side current increases; when the sampling current i dc Greater than a given i dc *, S7 is closed, S8 remains open, and the inductor freewheeling mode is entered, and the DC side current slowly decreases; when a large amount of energy is fed back from the motor end to the DC side, S7 is closed, S8 is closed, and the energy feedback mode is entered. The current flows through the resistor to consume the feedback energy, and the DC side current is limited to the threshold i fb *. Specific embodiment nine:

[0072] The difference between the ninth embodiment of the present invention and the eighth embodiment is that:

[0073] The present invention provides a computer-readable storage medium on which a computer program is stored. The program is executed by a processor to implement a current source inverter control method with an energy feedback loop. Specific embodiment ten:

[0075] The difference between the tenth embodiment of the present invention and the ninth embodiment is that:

[0076] The present invention provides a computer device, comprising a memory and a processor, wherein the memory stores a computer program, and the processor implements a current source inverter control method with an energy feedback loop when executing the computer program. Specific embodiment eleven:

[0078] The present invention mainly adopts the following technical solutions:

[0079] The topology structure includes a constant voltage source, a constant current source system composed of a switch tube denoted as S7, a diode and a DC side inductor, a feedback energy discharge loop composed of a switch tube denoted as S8 and a resistor, a basic current source inverter and a permanent magnet synchronous motor, etc. The current sensor is used to sample the DC side current i in real time. dc , when the sampling current i dc Less than a given i dc *, S7 opens, S8 remains open, and the power supply mode is entered, and the DC side current increases; when the sampling current i dc Greater than a given i dc*, S7 is closed, S8 remains open, and the inductor freewheeling mode is entered, and the DC side current slowly decreases; when a large amount of energy is fed back from the motor end to the DC side, S7 is closed, S8 is closed, and the energy feedback mode is entered. The current flows through the resistor to consume the feedback energy, and the DC side current is limited to the threshold i fb *.

[0080] The specific principles and implementation steps are as follows:

[0081] The specific circuit structure is:

[0082] Note: DC adjustable power supply U dc The positive end is the A end, and the negative end is the B end.

[0083] The A terminal is connected in series with the collector of the switch tube S7; the base of the switch tube S7 is connected to the driving signal; the emitter of the switch tube S7 is connected in series with the cathode of the diode VD7; the anode of the diode VD7 is connected in series with the emitter of the switch tube S8; the base of the switch tube S8 is connected to the driving signal; the collector of the switch tube S8 is connected in series with the B terminal;

[0084] The anode of diode VD7 is connected in series with the resistor and terminal B in sequence;

[0085] The emitter of the switch tube S7 is connected in series with the inductor L dc and the collector of the switch tube S1; the base of the switch tube S1 is connected to the driving signal; the emitter of the switch tube S1 is connected in series with the anode of the diode VD1; the cathode of the diode VD1 is connected in series with the collector of the switch tube S4; the base of the switch tube S4 is connected to the driving signal; the emitter of the switch tube S4 is connected in series with the anode of the diode VD4; the cathode of the diode VD4 is connected in series with the B terminal;

[0086] The emitter of the switch tube S7 is connected in series with the inductor L dc and the collector of the switch tube S3; the base of the switch tube S3 is connected to the driving signal; the emitter of the switch tube S3 is connected in series to the anode of the diode VD3; the cathode of the diode VD3 is connected in series to the collector of the switch tube S6; the base of the switch tube S6 is connected to the driving signal; the emitter of the switch tube S6 is connected in series to the anode of the diode VD6; the cathode of the diode VD6 is connected in series to the B terminal;

[0087] The emitter of the switch tube S7 is connected in series with the inductor L dc and the collector of the switch tube S5; the base of the switch tube S5 is connected to the driving signal; the emitter of the switch tube S5 is connected in series to the anode of the diode VD5; the cathode of the diode VD5 is connected in series to the collector of the switch tube S2; the base of the switch tube S2 is connected to the driving signal; the emitter of the switch tube S2 is connected in series to the anode of the diode VD2; the cathode of the diode VD2 is connected in series to the B terminal;

[0088] The cathode of diode VD1 is connected in series with motor phase A; the cathode of diode VD3 is connected in series with motor phase B; the cathode of diode VD5 is connected in series with motor phase C;

[0089] The cathode series capacitor C of diode VD1 fa One end: the cathode of diode VD3 is connected in series with capacitor C fb One end: the cathode of diode VD5 is connected in series with capacitor C fc One end; capacitor C fa The other end, capacitor C fb The other end, capacitor C fc The other end is connected.

[0090] According to the DC bus sampling current i dc and set the DC bus current i dc * and the given safe current value i during energy feedback fb *Compare to set the switch state of switch tubes S7 and S8. According to the on-off status of switch tubes S7 and S8, the new current source inverter topology with energy feedback loop is divided into four working modes, namely power supply mode, inductor freewheeling mode, and energy feedback mode;

[0091] When the novel current source inverter topology structure with an energy feedback loop is in a power supply mode, the switch tube S7 is turned on and the switch tube S8 is turned on;

[0092] When the new current source inverter topology with an energy feedback loop is in the inductive freewheeling mode, the switch tube S7 is turned off and the switch tube S8 is turned on;

[0093] When the novel current source inverter topology structure with an energy feedback loop is in the energy feedback mode, the switch tube S7 is turned off and the switch tube S8 is turned off.

[0094] The present invention can provide a stable DC side current with a switch tube and a diode, thereby ensuring the controllable operation of the motor, and on this basis, only a switch tube and a resistor are used to realize the discharge of the motor feedback energy, thereby ensuring the safety and reliability of the motor during four-quadrant operation with the simplest topology and low cost. Specific embodiment twelve:

[0096] Figure 1 The complete topology of the present invention includes a constant voltage source, a switch tube denoted as S7, a diode and a constant current source system composed of a DC side inductor, a switch tube denoted as S8 and a resistor composed of a feedback energy discharge loop, a basic current source inverter and a permanent magnet synchronous motor, etc. The current sensor is used to sample the DC side current i in real time. dc , when the sampling current i dc Less than a given i dc*, S7 opens, S8 remains open, and the power supply mode is entered, and the DC side current increases; when the sampling current i dc Greater than a given i dc *, S7 is closed, S8 remains open, and the inductor freewheeling mode is entered, and the DC side current slowly decreases; when a large amount of energy is fed back from the motor end to the DC side, S7 is closed, S8 is closed, and the energy feedback mode is entered. The current flows through the resistor to consume the feedback energy, and the DC side current is limited to the threshold i fb *.

[0097] The specific principles and implementation steps are as follows:

[0098] The specific circuit structure is:

[0099] Note: DC adjustable power supply U dc The positive end is the A end, and the negative end is the B end.

[0100] The A terminal is connected in series with the collector of the switch tube S7; the base of the switch tube S7 is connected to the driving signal; the emitter of the switch tube S7 is connected in series with the cathode of the diode VD7; the anode of the diode VD7 is connected in series with the emitter of the switch tube S8; the base of the switch tube S8 is connected to the driving signal; the collector of the switch tube S8 is connected in series with the B terminal;

[0101] The anode of diode VD7 is connected in series with the resistor and terminal B in sequence;

[0102] The emitter of the switch tube S7 is connected in series with the inductor L dc and the collector of the switch tube S1; the base of the switch tube S1 is connected to the driving signal; the emitter of the switch tube S1 is connected in series with the anode of the diode VD1; the cathode of the diode VD1 is connected in series with the collector of the switch tube S4; the base of the switch tube S4 is connected to the driving signal; the emitter of the switch tube S4 is connected in series with the anode of the diode VD4; the cathode of the diode VD4 is connected in series with the B terminal;

[0103] The emitter of the switch tube S7 is connected in series with the inductor L dc and the collector of the switch tube S3; the base of the switch tube S3 is connected to the driving signal; the emitter of the switch tube S3 is connected in series to the anode of the diode VD3; the cathode of the diode VD3 is connected in series to the collector of the switch tube S6; the base of the switch tube S6 is connected to the driving signal; the emitter of the switch tube S6 is connected in series to the anode of the diode VD6; the cathode of the diode VD6 is connected in series to the B terminal;

[0104] The emitter of the switch tube S7 is connected in series with the inductor L dc and the collector of the switch tube S5; the base of the switch tube S5 is connected to the driving signal; the emitter of the switch tube S5 is connected in series to the anode of the diode VD5; the cathode of the diode VD5 is connected in series to the collector of the switch tube S2; the base of the switch tube S2 is connected to the driving signal; the emitter of the switch tube S2 is connected in series to the anode of the diode VD2; the cathode of the diode VD2 is connected in series to the B terminal;

[0105] The cathode of diode VD1 is connected in series with motor phase A; the cathode of diode VD3 is connected in series with motor phase B; the cathode of diode VD5 is connected in series with motor phase C;

[0106] The cathode series capacitor C of diode VD1 fa One end: the cathode of diode VD3 is connected in series with capacitor C fb One end: the cathode of diode VD5 is connected in series with capacitor C fc One end; capacitor C fa The other end, capacitor C fb The other end, capacitor C fc The other end is connected.

[0107] Figure 2 The present invention is a logic flow chart for judging the switching of each mode. dc and set the DC bus current i dc * and the given safe current value i during energy feedback fb *Compare to set the switch state of switch tubes S7 and S8. According to the on-off status of switch tubes S7 and S8, the new current source inverter topology with energy feedback loop is divided into four working modes, namely power supply mode, inductor freewheeling mode, and energy feedback mode;

[0108] When the novel current source inverter topology structure with an energy feedback loop is in a power supply mode, the switch tube S7 is turned on and the switch tube S8 is turned on;

[0109] When the new current source inverter topology with an energy feedback loop is in the inductive freewheeling mode, the switch tube S7 is turned off and the switch tube S8 is turned on;

[0110] When the novel current source inverter topology structure with an energy feedback loop is in the energy feedback mode, the switch tube S7 is turned off and the switch tube S8 is turned off.

[0111] Figure 3 When the novel current source inverter topology with energy feedback loop of the present invention is adopted, the DC side current simulation waveform is shown; Set i dc *50A;

[0112] Figure 4 When the novel current source inverter topology with energy feedback loop is adopted, the DC side braking current simulation waveform is shown; Set i fb * is 52A;

[0113] Figure 5 The three-phase current simulation waveform of the motor is shown when the novel current source inverter topology with an energy feedback loop of the present invention is adopted.

[0114] It can be seen from the above simulation waveforms that the novel current source inverter topology with an energy feedback loop of the present invention can provide the required constant current for the current source inverter and can provide guarantee for the normal operation of the motor. When the motor feeds back energy to the front stage, the feedback energy is discharged in time to ensure that the DC bus current is controlled below the limit value.

[0115] The above is only a preferred implementation of a current source inverter topology structure and control method with an energy feedback loop. The protection scope of a current source inverter topology structure and control method with an energy feedback loop is not limited to the above embodiments. All technical solutions under this idea belong to the protection scope of the present invention. It should be pointed out that for those skilled in the art, several improvements and changes without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A current source inverter topology with an energy feedback loop, characterized in that: The topological structure includes a DC adjustable power supply U dc , switch tube S7, diode VD1, diode VD2, diode VD3, diode VD4, diode VD5, diode VD6, diode VD7, DC side inductor L dc , switch tube S1, switch tube S2, switch tube S3, switch tube S4, switch tube S5, switch tube S6, switch tube S7, switch tube S8, resistor R, capacitor C fa , capacitor C fb , capacitor C fc and PMSM motors; DC adjustable power supply U dc The positive terminal is connected in series with the collector of the switch tube S7; the base of the switch tube S7 is connected to the driving signal; the emitter of the switch tube S7 is connected in series with the cathode of the diode VD7; the anode of the diode VD7 is connected in series with the emitter of the switch tube S8; the base of the switch tube S8 is connected to the driving signal; the collector of the switch tube S8 is connected in series with the DC adjustable power supply U dc negative terminal.

2. The topological structure according to claim 1 is characterized in that: The anode of diode VD7 is connected in series with resistor R and DC adjustable power supply U dc The negative end of The emitter of the switch tube S7 is connected in series with the inductor L dc and the collector of the switch tube S1; the base of the switch tube S1 is connected to the driving signal; the emitter of the switch tube S1 is connected in series with the anode of the diode VD1; the cathode of the diode VD1 is connected in series with the collector of the switch tube S4; the base of the switch tube S4 is connected to the driving signal; the emitter of the switch tube S4 is connected in series with the anode of the diode VD4; the cathode of the diode VD4 is connected in series with the DC adjustable power supply U dc negative terminal.

3. The topological structure according to claim 2 is characterized in that: The emitter of the switch tube S7 is connected in series with the inductor L dc and the collector of the switch tube S3; the base of the switch tube S3 is connected to the driving signal; the emitter of the switch tube S3 is connected in series with the anode of the diode VD3; the cathode of the diode VD3 is connected in series with the collector of the switch tube S6; the base of the switch tube S6 is connected to the driving signal; the emitter of the switch tube S6 is connected in series with the anode of the diode VD6; the cathode of the diode VD6 is connected in series with the DC adjustable power supply U dc negative terminal.

4. The topological structure according to claim 3 is characterized in that: The emitter of the switch tube S7 is connected in series with the inductor L dc and the collector of the switch tube S5; the base of the switch tube S5 is connected to the driving signal; the emitter of the switch tube S5 is connected in series with the anode of the diode VD5; the cathode of the diode VD5 is connected in series with the collector of the switch tube S2; the base of the switch tube S2 is connected to the driving signal; the emitter of the switch tube S2 is connected in series with the anode of the diode VD2; the cathode of the diode VD2 is connected in series with the DC adjustable power supply U dc negative terminal.

5. The topological structure according to claim 4 is characterized in that: The cathode of diode VD1 is connected in series with the PMSM motor phase A; the cathode of diode VD3 is connected in series with the PMSM motor phase B; the cathode of diode VD5 is connected in series with the PMSM motor phase C; The cathode series capacitor C of diode VD1 fa One end: the cathode of diode VD3 is connected in series with capacitor C fb One end: the cathode of diode VD5 is connected in series with capacitor C fc One end; capacitor C fa The other end, capacitor C fb The other end and capacitor C fc The other end is connected.

6. The topological structure according to claim 5 is characterized in that: According to the DC bus sampling current i dc and set the DC bus current i dc * and the given safe current value i during energy feedback fb *Compare to set the switch status of switch tubes S7 and S8; According to the on-off status of the switch tube S7 and the switch tube S8, the topology structure is divided into four working modes, namely, power supply mode, inductor freewheeling mode, and energy feedback mode.

7. The topological structure according to claim 6 is characterized in that: When the topology structure is in the power supply mode, the switch tube S7 is turned on and the switch tube S8 is turned on; When the topology structure is in the inductive freewheeling mode, the switch tube S7 is turned off and the switch tube S8 is turned on; When the topology structure is in the energy feedback mode, the switch tube S7 is turned off and the switch tube S8 is turned off.

8. A method for controlling a current source inverter with an energy feedback loop, characterized in that: The method comprises the following steps: Use the current sensor to sample the DC side current i in real time dc , when the sampling current i dc Less than a given i dc *, S7 opens, S8 remains open, and the power supply mode is entered, and the DC side current increases; when the sampling current i dc Greater than a given i dc *, S7 is closed, S8 remains open, and the inductor freewheeling mode is entered, and the DC side current slowly decreases; when a large amount of energy is fed back from the motor end to the DC side, S7 is closed, S8 is closed, and the energy feedback mode is entered. The current flows through the resistor to consume the feedback energy, and the DC side current is limited to the threshold i fb *.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: The program is executed by a processor to implement the method according to claim 8.

10. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: The method of claim 8 is implemented when the processor executes the computer program.

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